Configuration and method for fixation of a filter to a catheter

ABSTRACT

An attachment configuration for a vascular filter assembly including a self-expanding filter member attached to a catheter body and constrained from expansion in a first configuration by a constraining sheath is presented. The attachment configuration includes an outer tube of material that is overlaid over an end of the filter member and bonded to the catheter body through cutouts disposed through the end of the filter member.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/954,908 filed Nov. 30, 2015, now U.S. Pat. No. 10,485,646;which is a continuation of U.S. patent application Ser. No. 13/917,579filed Jun. 13, 2013, now U.S. Pat. No. 9,199,059; which is acontinuation of U.S. patent application Ser. No. 13/333,811, filed Dec.21, 2011, now U.S. Pat. No. 8,808,323, issued Aug. 19, 2014; whichclaims priority to the U.S. Provisional Application Ser. No. 61/425,738,filed Dec. 21, 2010, each of which is hereby incorporated by referencein its entirety.

FIELD OF THE INVENTION

The present invention pertains generally to the field of vascularfilters for capturing embolic material in blood flow. More particularly,the present invention relates to a configuration and method forattachment of a vena cava filter near the distal end of a multi-lumencatheter.

BACKGROUND OF THE INVENTION

Venous thromboembolism (VTE), which includes deep venous thrombosis(DVT) and its sequela, pulmonary embolism (PE), is a significantclinical problem. It is the leading cause of preventable in-hospitalmortality in the United States and in other developed countries. It isestimated that as many as 50% of patients in intensive care units are atrisk of VTE and its comorbid conditions.

The accepted standard of care for patients with venous thromboembolism(VTE) is anticoagulant therapy. Inferior vena cava (IVC) filters arereserved for those patients who fail anticoagulant therapy, or have acomplication or contraindication to anticoagulant therapy. Until theearly 1970's, the only method of IVC interruption was surgical, eitherby clipping, ligation or plication. The first clinical experience of anendoluminally-placed device to interrupt IVC flow was reported byMobin-Uddin et al. in 1969. However, it was not until the introductionof a stainless steel umbrella-type filter by Greenfield et al. in 1973that an effective method of endoluminally trapping emboli whilesimultaneously preserving IVC flow became possible. Indeed, for manyyears, the Greenfield filter set a benchmark by which newer filters weremeasured. Early generations of filters were inserted by surgicalcut-down and venotomy. Eventually filters were able to be insertedpercutaneously: initially through large 24 Fr sheaths, though newergenerations of filters are able to be delivered through 6 Fr systems.

Despite the safety and efficacy of modern day filters, systemicanticoagulation remains the primary treatment for VTE. Eitherunfractionated or low molecular weight heparin followed by three monthsof oral anticoagulation in patients with proximal deep venous thrombosis(DVT) is approximately 94% effective in preventing pulmonary embolism(PE) or recurrent DVT. The routine placement of IVC filters in additionto anticoagulation in patients with documented DVT was investigated byDecousus et al. in a randomized trial. (Decousus H, Leizorovicz A,Parent F, et al. A clinical trial of vena caval filters in theprevention of pulmonary embolism in patients with proximal deep-veinthrombosis. N Engl J Med 1998; 338:409-415). This study revealed thatthe use of a permanent filter in addition to heparin therapysignificantly decreased the occurrence of PE within the first 12 dayscompared to those without a filter. However, no effect was observed oneither immediate or long-term mortality, and by 2 years, the initialbenefit seen in the group of patients with filters was offset by asignificant increase in the rate of recurrent DVT.

Despite the efficacy of anticoagulant therapy in the management of VTE,there are certain situations and conditions in which the benefits ofanticoagulation are outweighed by the risks of instituting such atherapy. These include contraindications and complications ofanticoagulant therapy. In such circumstances, there may be absolute orrelative indications for filter insertion.

Well-founded concerns over the long-term complications of permanent IVCfilters, particularly in younger patients in need of PE prophylaxis witha temporary contraindication to anticoagulation, has led to thedevelopment of temporary and retrievable filters. Temporary filtersremain attached to an accessible transcutaneous catheter or wire. Thesehave been used primarily in Europe for PE prophylaxis duringthrombolytic therapy for DVT. Currently these devices are not approvedfor use in the United States. Retrievable filters are very similar inappearance to permanent filters, but with modifications to the cavalattachment sites and/or hooks at one end that can facilitate theirremoval. Retrievable filters are currently available in the UnitedStates, examples of these include the Gunther Tulip (Cook Inc.), OptEase (Cordis Corp.), and Recovery nitinol filters (Bard PeripheralVascular, Tempe, Ariz.) (Lin P H, et al., Vena caval filters in thetreatment of acute DVT. Endovascular Today 2005; January:40-50). Thetime limit of retrievability is in part dependent on the rate ofendothelialization of the device, which typically occurs within 2 weeks.However, differences in design may extend the time period in which thefilter may be safely retrieved.

Currently no consensus exists as to which patients have an indicationfor a retrievable filter. However, it is generally accepted thatpatients at high risk for pulmonary embolism or with documented PE andwith a temporary contraindication to anticoagulation are candidates.Certain circumstances preclude the placement of a filter in theinfrarenal IVC. This includes thrombus extending into the infrarenalIVC, renal vein thrombosis or pregnancy. The safety of suprarenalplacement of IVC filters is well documented, with no reported instancesof renal dysfunction and no differences in the rates of filtermigration, recurrent PE or caval thrombosis.

The rate of upper extremity DVT is on the rise. This is predominantlydue to an increasing number of patients having short- and long-termupper extremity central venous access catheters. In one study, 88% ofpatients found to have an upper extremity DVT had a central venouscatheter present at the site of thrombosis at the time of diagnosis orwithin the previous two weeks. Pulmonary embolism may complicate upperextremity DVT in 12-16% of cases. In patients who have such acomplication or contraindication to anticoagulation, a filter can besafely placed immediately below the confluence of the brachiocephalicveins. However, misplacement of an SVC filter is theoretically morelikely than with an IVC filter because of the relatively short targetarea for deployment.

In addition to providing a vascular filter for endoluminally trappingemboli while simultaneously preserving vascular flow, vascular filterassemblies (“VFA's”) known in the art include additional featuresincluding, for example, a filter geometry in which the proximal portionof the filter, relative to the axis of blood flow, has largerinterstitial openings to permit thrombus or embolic material to flowinto the filter, while the distal portion of the filter, again relativeto the axis of blood flow, has relatively smaller interstitial openingsthat capture the thrombus or embolic material within the filter. Notethat a jugular approach necessitates that the VFA be introducedretrograde relative to the vector of blood flow within the vena cava,i.e., the VFA is introduced through the jugular vein and directedinferiorly toward an infrarenal position. Additionally, since the bloodflow opposes the distal end of the VFA and passes toward the proximalend, the vena cava filter must open inferiorly such that its largestdiametric section in apposition to the vessel walls opens toward thedistal end of the VFA rather than toward the proximal end of the VFA aswith the femoral approach.

The VFA may include fluid infusion ports positioned in the sidewall ofthe central access catheter to which the vascular filter is attached.Such fluid infusion ports may have a directional flow orientation suchthat any or all regions of the space delimited by the vena cava filtermay be exposed to fluid flow therefrom.

The VFA may include proximal and distal ports disposed in the centralaccess catheter and positioned entirely or partially distant from anopen area bounded by the filter permit measuring pressure and/or flowvelocity across the filter as a determinant of extent of capture ofembolic material in the filter or for measuring flow rate at theposition of the filter member as a positional indicator within the body.Such pressure and/or flow sensing may be accomplished by a hydrostaticfluid column in communication with each of the proximal and distal portsand a pressure transducer operably associated with a proximal end of thecentral access catheter.

The proximal and distal ports, and lumens associated therewith, may alsoprovide means for introducing fluids, such as an anticoagulant,thrombolytic or other bioactive agents, contrast medium, bloodtransfusions, intravenous fluids or other medications. Alternatively,the proximal and distal ports may be used for withdrawal or evacuationof fluids or other material through the catheter. The multiple infusionports also provide a means for introducing a flushing medium, such assaline, under elevated pressure to produce mechanical thrombolysis orinduce thrombolysis by the infusion of thrombolytic agents directly tothrombus within the filter.

A need exists for a configuration and method for attachment of thefilter to a catheter that is mechanically reliable and simple tomanufacture.

SUMMARY OF THE INVENTION

An attachment configuration disposed at a proximal end of a filtermember comprises a catheter body coaxially disposed through the proximalend of the filter member; a plurality of cutouts disposed coaxiallyaround the proximal end of the filter member; and a thin tube coaxiallydisposed around the plurality of cutouts, wherein the thin tube engagesthe at least a portion of the catheter body and the thin tube fixedlyattaches the proximal end of the filter member through the plurality ofcutouts.

A method for attaching a proximal end of a filter member, comprisesdisposing a thin tube over a catheter body and over at least a portionof the proximal end of the filter member, wherein the proximal endincludes a plurality of cutouts; disposing a heat shrink tube coaxiallyover the thin tube; and fusing the thin tube to the catheter bodythrough the plurality of cutouts to attached the proximal end of thefilter member to the catheter body.

The foregoing and other features and advantages of the invention areapparent from the following detailed description of exemplaryembodiments, read in conjunction with the accompanying drawings; whereinlike structural or functional elements may be designated by likereference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of an exemplary vascular filterassembly in a first configuration.

FIG. 2 is a side elevational view of the exemplary vascular filterassembly of FIG. 1 in a second configuration.

FIG. 3 is a close-up view of a distal end of the exemplary vascularfilter assembly of FIG. 1 in a second configuration.

FIG. 4A is a close-up view of area 4A of FIG. 3 for an attachmentconfiguration for the exemplary vascular filter assembly; FIG. 4B is across-sectional view of the attachment configuration of FIG. 4A takengenerally along the line 4B-4B of FIG. 4A; FIG. 4C is an alternativeattachment configuration for the vascular filter assembly; FIG. 4D showsan alternative configuration for the cutouts in the attachmentconfiguration; FIG. 4E shows an exploded view of the proximal end 404including the alternating pattern from FIG. 4D; FIG. 4F shows aperspective view of the proximal end 404 including the alternatingpattern of cutouts from FIG. 4D; FIG. 4G shows an alternativeconfiguration for the cutouts in the attachment configuration 402; andFIG. 4H shows an alternative configuration for the cutouts in theattachment configuration.

FIG. 5 is a cross-sectional view of an exemplary vascular filterassembly taken generally along line 5-5 of FIG. 1.

FIG. 6 is a cross-sectional view of another exemplary vascular filterassembly taken generally along line 5-5 of FIG. 1.

The foregoing and other features and advantages of the invention areapparent from the following detailed description of exemplaryembodiments, read in conjunction with the accompanying drawings; whereinlike structural or functional elements may be designated by likereference numerals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the accompanying Figures like structural or functional elements aredesignated by like reference numerals, e.g., 16, 116, 216, 316, 416represent similar structural or functional elements across differentembodiments disclosed herein.

As used in this application, unless otherwise specifically stated, theterms “proximal” and “distal” are intended to refer to positionsrelative to a longitudinal axis of the VFA. Those skilled in the artwill understand that the VFA has a distal end which is first insertedinto a patient and a proximal end which opposite the distal end.Additionally, the terms “inferior” or “inferiorly” are intended to referto the anatomic orientation of being in a direction away from thepatient's head while the terms “superior” or “superiorly” are intendedto refer to the anatomic orientation of being toward the patient's head.

The embodiments disclosed herein may be configured for either a femoralapproach or a jugular approach to the inferior vena cava. Vena cavafilters are typically deployed infrarenaly, but may also be deployedsuprarenaly. It will be understood that within the inferior vena cavablood flow is superior, i.e., toward a patients head. Thus, in allembodiments, the vena cava filter will be positioned so that it opensinferiorly, i.e., away from the patient's head and toward the directionof the blood flow. It will be appreciated, therefore, that in theembodiments disclosed herein, the vena cava filter will have a differentaxial orientation on the central access catheter depending upon whetherthe device is intended for use in a femoral approach or a jugularapproach.

The most common imaging modality used for filter insertion isfluoroscopy, performed either in an interventional suite or an operatingroom. Bedside placement of filters has inherent advantages, particularlyfor critically ill patients in intensive care settings where transportcan be avoided. Portable fluoroscopy, surface duplex ultrasound andintravascular ultrasound (IVUS) have all been used to assist withbedside filter placement.

Referring to FIGS. 1 and 2, an exemplary vascular filter assembly(“VFA”) 100 is illustrated in a first configuration 200 and a secondconfiguration 300, respectively. The exemplary VFA 100 includes acatheter body 102 having a self-expanding filter member 104 coupledthereto. A sheath 106 is disposed over the filter member 104 and thecatheter body 102 such that the filter member 104 is at least partiallyconstrained from expansion in the first configuration 200. The filtermember 104 is constrained from expansion within an interior space 108(See FIGS. 5 and 6) defined between the sheath 106 and the catheter body102.

The filter member 104 may be slidably or fixedly attached to thecatheter body 102 or may be removably coupled to the catheter body 102for deployment as either a permanent filter or as a temporary andretrievable vena cava filter. Removable coupling of the filter member104 to the catheter body 102 may be accomplished with a variety ofrelease and retrieval mechanisms operably associated with the catheterbody 102. Non-limiting examples of such release and retrieval mechanismsare disclosed, for example, in Angel U.S. Patent Application PublicationNo. 2009/0062840 and Angel et al. U.S. Patent Application PublicationNo. 2010/0217304, incorporated by reference in their entirety herein.

Referring to FIG. 5, in one embodiment, the catheter body 102 comprisesa single lumen 110. The single lumen 110 is in fluid communication withthe interior space 108 via at least one port 112 disposed through thesidewall 114 of the catheter body 102.

Referring to FIG. 6, in other embodiments, the catheter body 102comprises multiple lumens 116. In one embodiment, the catheter body 102includes at least one first port 118 disposed through a sidewall 120thereof and providing fluid communication between the interior space 108and a first lumen 122. The catheter body 102 may further include atleast one second port 124 disposed through a sidewall 126 thereof andproviding fluid communication between the interior space 108 and asecond lumen 128. Bioactive agents, flushing fluids, pressurizedmechanical thrombolytic fluids, or other fluids may be infused throughthe single lumen 110 or the first and second lumens 122, 128 and out ofthe at least one port 112, the at least one first port 118, and the atleast one second port 124 to pass into the interior space 108 andultimately into a patient's venous system for either local or systemiceffect.

Again referring to FIGS. 1 and 2, the sheath 106 may be concentricallydisposed over the catheter body 102 such that relative longitudinalmovement of the catheter body 102 and the sheath 106 (as indicated byarrows labeled M in FIG. 1) either exposes the filter member 104 in thesecond configuration 300 or captures the filter member 104 within thesheath 106 in the first configuration 200. The sheath 106 may terminatein an annular opening 130 (corresponding to the interior space 108) at adistal end 132 thereof. A distal hub 134 may be coupled to a proximalend 136 of the sheath 106.

Referring to FIGS. 1, 2, 5 and 6, an infusion port 138 may be provideddisposed through a sidewall 140 of the sheath 106. The infusion port 138is adapted to receive a tube 142 that may include a luer or other typeof fitting 144 at a proximal end thereof. The infusion port 138 providesfluid communication between an exterior of the distal hub 134 and theinterior space 108, as illustrated in FIGS. 5 and 6.

A proximal hub 148 may be coupled to a proximal end 150 of the catheterbody 102. The proximal hub 148 and the distal hub 134 may be removablyengageable with each other. A plurality of fluid lines, for example,fluid lines L1, L2, L3, L4, may communicate with the proximal hub 148,as illustrated in FIGS. 1 and 2. Each of the fluid lines L1, L2, L3, andL4 may be in fluid communication with at least one of the single lumen110, the first and second lumens 122, 128, or other lumens within thecatheter body 102. When the VFA is in the second configuration 300, theproximal and distal hubs 148, 134 may be removably engaged to form a hubassembly 152 that inhibits relative motion of the catheter body 102 andthe sheath 106. Vascular filter assemblies and features thereof such asstructure, orientation, and materials comprising the filter member 104,the sheath 106 and/or the catheter body 102 including single or multiplelumens that may be instructional or useful in the current applicationmay be found in the disclosures of, for example, Angel U.S. PatentApplication Publication No. 2009/0062840 and Angel et al. U.S. PatentApplication Publication No. 2010/0217304, incorporated by reference intheir entirety.

Referring to FIG. 3-4B, in one embodiment of a VFA 400, an embodiment ofattachment configuration 402 disposed at a proximal end 404 of thefilter member 104 attaches the filter member 104 to the catheter body102. The general longitudinal axis L and axial axis A is shown in FIG.3. The catheter body 102 is coaxially disposed through the proximal end404 of the filter member 104. Preferably, the catheter body 102 iscoaxially disposed through the interior of the proximal end 404, asshown in FIG. 4B. However, alternatively, the catheter body 102 may becoaxially disposed on the exterior of the proximal end 404. In oneembodiment, the proximal end 404 of the filter member 104 includes aplurality of cutouts 408 disposed coaxially around the proximal end 404of the filter member 104. A thin tube 406 is disposed coaxially aroundthe plurality of cutouts 408 as to engage at least a portion of thecatheter body 102 through the plurality of cutouts 408.

In one embodiment, the material of a thin tube 406 (See FIGS. 4A and 4B)and the material of the catheter body 102 are the same as to be fusedtogether through the plurality of cutouts 408. However, in otherembodiments, the proximal end 404 of the filter member 104 may notinclude cutouts 408 or may include cutouts 408 having a diamond shape asgenerally shown in FIG. 4A or other patterns or shapes, including, butnot limited, triangular, pyramidal, square, rectangular, polygonal,pentagonal, hexagonal, octagonal, circular, elliptical, open-endedcircular shape, semi-circular shapes, coiled shapes, zig-zag shapes,sinusoidal shapes, spaced-lines, and the like. Alternatively, thecutouts 408 may include a combination of different shapes and patterns,as further explained below.

The plurality of cutouts 408 include a width W extending generally alongthe longitudinal axis of the proximal end 404 and a height H extendinggenerally along the axial axis of the proximal end 404, as shown in FIG.4A. The width W and height H of the plurality of cutouts 408 may beadjusted as to maximize the engagement of the thin tube 406 through thecutouts 408 and with the catheter body 102. In one embodiment, the widthW of the cutouts 408 is greater than the height H of the cutouts as tomaximize the longitudinal engagement of the proximal end 404 with thecatheter body 102. Generally speaking, the filter member 104 experienceslongitudinal forces once the filter member 104 is in the secondconfiguration 300, due to direction of blood flow and capturedembolisms. As shown in FIG. 4B, the proximal end 404 includes athickness Tp, whereby the plurality of cutouts 408 traverse the entirethickness Tp of the proximal end. Also, the thin tube 406 includes athickness Tt. In one embodiment, the thickness Tt of the thin tube 406is less than the thickness Tp of the proximal end 404 such that the thintube 406 may properly traverse the thickness Tp of the proximal end 404to engage the catheter body 102. The thin tube 406 includes a diameterDt, the proximal end 404 includes a diameter Dp, and the multilumencatheter body 102 includes a diameter Dm. Preferably, the diameter Dt ofthe thin tube 406 is greater than the diameter Dp of the proximal end404, and the diameter Dp of the proximal end 404 is greater than thediameter Dm of the catheter body 102. Alternatively, the diameters Dt,Dp, and Dm may be of the similar sizes, such that diameter Dp isradially expandable to constrict onto the catheter body 102, and thediameter Dt radially expands to constrict onto the proximal end 404.

In one embodiment, the plurality of cutouts 408 are longitudinallydisposed throughout the proximal end 404 of the filter, that is thecutouts 408 extend generally parallel along the longitudinal axis. Thelongitudinal extension of the cutouts 408 provides a series oflongitudinal rows of cutouts 410, i.e. a first longitudinal row ofcutouts 410 a, a second longitudinal row of cutouts 410 b, and a thirdlongitudinal row of cutouts 410 c, as shown in FIG. 4A. Generally, atleast two rows of the longitudinal cutouts are provided. Thelongitudinal rows of cutouts 410 a, 410 b, and 410 c may generallyinclude at least three cutouts 408 along the longitudinal axis,alternatively, the longitudinal row of cutouts may include at least twocutouts 408, at least four cutouts, at least five cutouts, at least sixcutouts, or at least between two and 20 cutouts along the longitudinalaxis. The number of cutouts 408 along the longitudinal axis for eachlongitudinal row 410 a, 410 b, and 410 c may be the same or different,or alternatively, the number of cutouts 408 for each longitudinal row ofcutouts 410 a, 410 b, and 410 c may be selected based upon the degree ofattachment for the proximal end 404 to the catheter body 102. Whilethree longitudinal rows of cutouts 410 a, 410 b, and 410 c are shown inFIG. 4A, the attachment configuration 402 may include at least two rowsof cutouts, at least four rows of cutouts, at least five rows ofcutouts, at least six rows of cutouts, or at least between two and 20rows of cutouts along the longitudinal axis. In one embodiment, eachcutout 408 in the longitudinal row of cutouts is adjacent or touchingadjacent cutouts 408 along the Width W of the cutouts, such thatadjacent cutouts 408 are touching in an end-to-end fashion along theWidth W. Alternatively, adjacent cutouts 408 in each longitudinal row ofcutouts 410 may include a space between adjacent ends of the cutouts 408along the Width of the cutouts 408, as further explained below.

Also, the plurality of cutouts 408 may be disposed in a series of axialcolumn of cutouts 420, i.e. a first axial column of cutouts 420 a, asecond axial column of cutouts 420 b, and a second axial column ofcutouts 420 c, as shown in FIG. 4A. The thin tube 406 may be coaxiallydisposed over the second axial column of cutouts 420 b and the thirdaxial column of cutouts 420 c. Alternatively, the thin tube 406 may becoaxially disposed to be partially overlapping the first axial column ofcutouts 420 a, or the thin tube 406 may not be coaxially disposed overthe first axial column of cutouts 420 a. Alternatively, the thin tube406 may be coaxially disposed over first and second axial columns ofcutouts 420 a, 420 b. The axial column of cutouts 420 a, 420 b, and 420c may generally include at least three cutouts 408 along the axial axis,alternatively, the axial column of cutouts 420 may include at least twocutouts 408 along the axial axis, at least four cutouts, at least fivecutouts, at least six cutouts, or at least between two and twentycutouts along the axial axis. The number of cutouts 408 along the axialaxis for each axial column of cutouts 420 a, 420 b, and 420 c may be thesame or different, or alternatively, the number of cutouts 408 for eachcolumn of cutouts 420 a, 420 b, and 420 c may be selected based upon thedegree of attachment for the proximal end 404 to the catheter body 102.While three axial column of cutouts 420 a, 420 b, and 420 c are shown inFIG. 4A, the attachment configuration 402 may include at least two axialcolumns of cutouts, alternatively, at least four axial columns, at leastfive axial columns, at least six axial columns, or at least between twoand twenty axial columns along the axial axis. In one embodiment, eachcutout 408 in the axial column of cutouts is adjacent or touchingadjacent axial cutouts 408, such that adjacent cutouts 408 are touchingin an end-to-end fashion along the height H of the cutouts 408.Alternatively, adjacent cutouts 408 in each axial column of cutouts 410may include a space between adjacent ends of the cutouts 408 along theheight H of the cutouts 408, as further explained below.

FIG. 4C shows an alternative configuration for the cutouts in theattachment configuration 402, where the cutouts 408 include a circularshape. In this embodiment, the first longitudinal row of cutouts 410 aincludes a space or gap 412 between the second longitudinal row ofcutouts 410 b. Also, the first axial column of cutouts 420 a includes aspace or gap 414 between the second axial column of cutouts 420 b.Additionally, the thin tube 406 is coaxially disposed only over thesecond axial column and the third axial column of cutouts 420 b, 420 c.This coaxial disposition of the thin tube 406 attaches the proximal end404 of the filter member 104 through the second axial column and thethird axial column of cutouts 420 b, 420 c to the catheter body 102while permitting the first axial column of cutouts 420 a. And the thirdaxial column of cutouts 420 c includes a greater Width W and Height Hcompared to the second and first axial column of cutouts 420 a, 420 b.

FIG. 4D shows an alternative configuration for the cutouts in theattachment configuration 402 including alternating cutouts of diamondshapes 440 and semi-circular shapes 430. The first, third, and fifthlongitudinal row of cutouts 410 a, 410 c, 410 e is a repeating patternof semi-circular shape cutouts 430, whereby the semicircular shapecutouts 430 include a first leg 432 and a second 434 encircling thesemi-circular cutout 430. The second, fourth, and sixth longitudinalrows of cutouts 410 b, 410 d, and 410 f include a repeating pattern ofdiamond shaped cutouts 440, whereby the diamond shaped cutouts 440include a strut-like enclosure with a top half 442 and a bottom half 444enclosing the diamond shaped cutouts 440. The top half 442 and thebottom half 444 project generally along the axial axis of the proximalend 404. The diamond shaped cutouts 440 includes a first end 446 and asecond end 448 projecting generally along the longitudinal axis of theproximal end 404. The top half 442 and the bottom half 444 of thediamond-shaped cutouts 440 are fixedly attached to the first legs 432 ofthe semi-circular cutouts 430. The first end 446 and the second end 448generally cover at least a portion of the semi-circular cutouts 430,whereby the first end 446 and the second end 448 of adjacentdiamond-shaped cutouts 440 include a space or gap 450 therebetween. Inone embodiment, the gap 450 between the first axial column of cutouts420 a and the second axial column of cutout 420 b is where the distalend of the thin tube 460 is positioned for attaching the proximal end404 to the catheter body 102. Such an alternating pattern for theattachment configuration 402 may be radially expandable as to coaxiallyfit over the catheter body 102.

FIG. 4E shows an exploded view of the proximal end 404 including thealternating pattern from FIG. 4D. Here, the first longitudinal row ofcutouts 410 a includes the diamond-shaped cutouts 440, which extendinggenerally along top of the proximal end 404. The second longitudinal rowof cutouts 410 b includes the semicircular shape cutouts 430, the thirdlongitudinal row of cutouts 410 c includes the diamond-shaped cutouts440, the fourth longitudinal row of cutouts 410 d include thesemicircular shaped cutouts 430, the fifth longitudinal row of cutouts410 e includes the diamond shaped cutouts 440. FIG. 4F shows aperspective view of the proximal end 404 including the alternatingpattern of cutouts from FIG. 4D. Here, the first longitudinal row ofcutouts 410 a includes the semicircular shape cutouts 430, whichextending generally along top of the proximal end 404. The secondlongitudinal row of cutouts 410 b includes the diamond-shaped cutouts440, the third longitudinal row of cutouts 410 c includes thesemicircular shaped cutouts 430.

FIG. 4G shows an alternative configuration for the cutouts in theattachment configuration 402 including alternating cutouts of anopen-ended circular shapes 460 on the first end 462 of the proximal end404, an elliptical shaped cutouts 470 on the second end 464, and acoiled shape cutout 480 intermediate the open-ended circular shapecutouts 460 and the elliptical shaped cutouts 470. In this attachmentconfiguration 402, the first axial column of cutouts 420 a includes theopen-ended circular shaped cutouts 460, the second axial column ofcutouts 420 b includes the coiled shaped cutouts 480, and the thirdaxial column of cutouts 420 c includes the elliptical shaped cutouts.The coiled shaped cutouts 480 provided flexibility while also permittingthe thin tube 406 to engage and attached to the catheter body 102between the coils. The elliptical shaped cutouts 470 may engage a detentor projection 490 on the catheter body 102 as to prevent longitudinalmovement of the proximal end 404 upon attachment of the thin tube 406.The detent or projection 490 fitted to the elliptical shaped cutouts 470may provide a point of connection for a user operating the catheter andthe filer member 104.

FIG. 4H shows an alternative configuration for the cutouts in theattachment configuration 402 including an open ended shape cutout 460including an opening 468 facing the second end 464 of the proximal end404. The opening 468 may allow for radial expansion, while theopen-ended shape cutout 460 may engage a projection or detent 490extending from the catheter body 102 as to prevent longitudinal movementof the proximal end 404 upon being attached to the catheter body 102 bythe thin tube 406.

Referring now to all embodiments, the attachment configuration 402 iscreated by a thermal bonding process including first inserting polymercoated metal wires into a single lumen of the single lumen catheter body102 or into multiple lumens of the multilumen catheter body 102. In oneembodiment, the polymer coating for the metal wires ispolytetrafluorethylene (PTFE), although other polymers may be used asindicated below. The polymer coated metal wires placed into the lumen orlumens inhibit closure or filling of the lumen or lumens in the rest ofthe process and therefore function to maintain patency of the lumen orlumens.

Next, a thin tube 406 is coaxially disposed over the catheter body 102and coaxially over at least a portion of the proximal end 404 of thefilter member 104 as illustrated in FIG. 4A. In one embodiment, the tube406 comprises a polyether block amide, for example, sold under thetrademark name PEBAX®, available from the Arkema Company, ColombesCedex, France. In other embodiments, the thin tube 406 may be made fromother materials. In one embodiment, the thin tube 406 is made from thesame material as the catheter body 102, for example, a polyether blockamide sold under the trademark name PEBAX®. In this embodiment, thecutouts 408 in the end 404 of the filter member 104 allow the samematerial of the thin tube 406 and the catheter body 102 to flow togetherthrough the cutouts 408 when melted.

A polyethylene terephthalate (PET) heat shrink tube (not shown) isdisposed over the thin tube 406. Alternative polymer heat shrink tubesmay be used, such as fluorinated ethylene propylene (FEP) provided thatthe polymer heat shrink tube is not the same material as the thin tube406 or the catheter body 102. In one embodiment, the thin tube is fusedto the catheter body 102 through the plurality of cutouts 408 using, forexample, hot air as provided from a hot air nozzle. In otherembodiments, the fusing may be supplied in alternative ways such as athermal bonder, thermoplastics, and the like. For portions of theproximal end that are not to be bonded by the thin tube 406, a heatshield may be used to protect such areas of the proximal end 404 toprevent fusing. Heating the attachment configuration 402 causes thematerial of the thin tube 406 and the material of the catheter body 102to melt together. In one embodiment, the melting together of the thintube 406 and the catheter body 102 causes contact and bondingtherebetween through the cutouts 408. Effectiveness of such contact andbonding may be increased in embodiments where the thin tube 406 and thecatheter body 102 are made of the same material, which upon melting canflow together through the cutouts 408 into a seamless monolithicstructure that encapsulates the end 404 of the filter 104 as illustratedin FIGS. 4A-4G. Following the step of applying heat to melt the thintube 406, the PET heat shrink tube may be removed thus completing theprocess of making the attachment configuration 402.

The catheter body 102 in the region of the attachment configuration 402may be the single lumen catheter body 102 as illustrated in FIG. 5, orthe multilumen catheter body as illustrated in FIG. 6, or as configuredincluding other lumens different from those illustrated in FIG. 6. Itshould also be noted that any or all of the lumens in the multilumencatheter body of FIGS. 4B and/or FIG. 6 may extend only partiallythrough the catheter body 102 or entirely through the catheter body 102.

Alternative polymeric materials may be included for the thin tube 406,such as, for example, polytetrafluoroethylene (PTFE), ethylenetetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP),polyoxymethylene (POM, for example, as sold under the trademark DELRIN®available from DuPont), polybutylene terephthalate (PBT), polyetherblock ester, polyurethane, polypropylene (PP), polyvinylchloride (PVC),polyether-ester (for example, a polyether-ester elastomer as sold underthe trademark ARNITEL® available from DSM Engineering Plastics),polyester (for example, a polyester elastomer as sold under thetrademark HYTREL® available from DuPont), polyamide (for example, assold under the trademark DURETHAN® available from Bayer or as sold underthe trademark CRISTAMID® available from Elf Atochem), elastomericpolyamides, block polyamide/ethers, polyether block amide (PEBA, forexample, as sold under the trade name PEBAX® available from Arkema,Inc.), silicones, polyethylene (PE), Marlex high-density polyethylene,Marlex low-density polyethylene, linear low density polyethylene,polyethylene terephthalate (PET), polyetheretherketone (PEEK), polyimide(PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenyleneoxide (PPO), polysulfone, nylon, nylon-12 (as sold under the trademarkGRILAMID® available from EMS American Grilon), perfluoro(propyl vinylether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy,polyvinylidene chloride (PVdC), polycarbonates, ionomers, biocompatiblepolymers, other suitable materials, or mixtures, combinations,copolymers thereof, polymer/metal composites, and the like.Alternatively, the thin tube 406 may be fabricated from shape memorymaterials, including shape memory metals and shape memory polymers(“SMM”).

The filter member 104 and the proximal end 404 may be fabricated ofbiocompatible materials, such as shape memory metal alloys, superelasticmaterials or elastic materials, including, without limitation, titanium,vanadium, aluminum, nickel, tantalum, zirconium, chromium, silver, gold,silicon, magnesium, niobium, scandium, platinum, cobalt, palladium,manganese, molybdenum and alloys thereof, such aszirconium-titanium-tantalum alloys, cobalt-chromium-molybdenum alloys,nitinol, and stainless steel. Alternatively, biocompatible polymers maybe used to fabricate the filter member 104 and the proximal end 404. Theplurality of cutouts may be formed by laser cutting, wet or dry etching,and similar methods for creating cutouts in metal materials.

In addition, a placement sensor may be coupled to the proximal end 404to determine the degree of attachment for the configuration 402. Such aplacement sensor may provide indications on whether the proximal end 404is moving along the longitudinal axis of the catheter body 102 afteraffixation. If movement of the proximal end 404 is detected by the user,the user may then retract the catheter body as to prevent the filtermember 104 from being retracted to the first configuration 200 or thefilter member being dislodged in the patient.

While the embodiments disclosed herein are not limited to specificdimensional sizes of the catheter body 102, the sheath 106, or any lumendiameter or port dimension, an exemplary outer diameter size of thesheath 106 is between about 6 Fr (2.0 mm) and about 9 Fr (3.0 mm). Anexemplary outer diameter size of the catheter body 102 is between about4 Fr (1.3 mm) and 7 Fr (2.4 mm).

An attachment configuration for a vascular filter assembly (“VFA”)including a self-expanding filter member attached to a catheter body andconstrained from expansion in a first configuration by a low profileconstraining sheath is presented. The attachment configuration is simpleto produce and provides an effective and reliable bond between thefilter member and the catheter body.

Vena cava filter placement frequently occurs concomitantly with centralaccess line placement or in critically ill patients that already have acentral access line in place. Heretofore, however, there have been nodevices which combine the function of a central access catheter and aremovable vena cava filter.

The embodiments disclosed herein benefit from an improved method forcoupling a multi-lumen catheter to a vena cava filter such that themulti-lumen catheter is useful both as a central venous access catheterfor administration of intravenous fluids, bioactive agents, contrastagents, flushing agents, pressurized fluids for mechanical thrombolysisand/or withdrawal of blood samples and for capture of thrombus oremboli.

The embodiments disclosed herein further benefit from a filter geometryin which the proximal portion of the filter, relative to the axis ofblood flow, has larger interstitial openings to permit thrombus orembolic material to flow into the filter, while the distal portion ofthe filter, again relative to the axis of blood flow, has relativelysmaller interstitial openings that capture the thrombus or embolicmaterial within the filter. Another way to view this aspect is that thestructure of the filter includes a greater open surface area exposed tothe flow of embolic material into the filter at its proximal end, whilethe distal end has smaller open surface area exposed to the flow ofembolic material to capture the embolic material in the distal end ofthe filter member. More specifically, regardless of whether theembodiments disclosed herein is delivered by a jugular approach or afemoral approach, the filter geometry is such that the largerinterstitial openings of the filter are positioned inferiorly along alongitudinal axis of the filter. The embodiments disclosed herein alsobenefit from combining the functions of an inferior vena cava (IVC)filter and a multilumen central venous catheter. The embodimentsdisclosed herein may be placed in the inferior vena cava via the femoralvein for the prevention of PE, as well as access to the central venoussystem.

EXAMPLES

A study compared the ease of in vitro placement, retrieval, deployment,and clot-trapping effectiveness a Vena Cava Filter Catheter (VCFC)utilizing the embodiments disclosed herein compared to other retrievableIVC filters. (Angel L, Guerra R, Atkinson E, et al. In Vitro Placementand Effectiveness of the Angel™ Vena Cava Filter Catheter), incorporatedby reference herein.

The study was conducted in a vena cava simulator with tubing diametersof 16 mm, 19 mm, 25 mm and 30 mm. Human blood has a mean density of1.055 g/mL and a mean viscosity of 0.035 St at a mean temperature of 37C. Therefore, the vena cava simulator mimicked physiological conditionsby using a blood analog aqueous solution, composed of 52% glycerin byweight with a density of 1.12 g/ML and a viscosity of 0.032 St that wascirculated at 37±2° C.

The filter was expanded as the outer sheath was pulled back and securedin position. The filter was retrieved by reversing the process andcollapsing the filter as the multilumen catheter was pulled back intothe outer sheath. The filter was tested with 150 cylindrical clots thatsimulated emboli of four different sizes: 3×5 mm, 3×10 mm, 5×10 mm and5×20 mm. The clot-trapping effectiveness of the VCFC was compared toother retrievable IVC filters including the Cook Gunther Tulip, BardRecovery, and Bard G2.

The VCFC utilizing the embodiments disclosed herein was successfullydeployed 24 times at various vena cava diameters. All the tested filterswere deployed in the required area with full apposition against the wallof the simulated vena cava at all times. No migration was observed postdeployment or during the clot capture efficiency testing. Filterefficiency increased proportionally to the cylindrical clot size andinversely to the test tube inner diameter. The clot capturing rate ofthe VCFC utilizing the embodiments disclosed herein was similar to thatof the Tulip, Recovery, and G2 filters at an IVC diameter of 16 mm and19 mm, but was superior in capturing small clots at a diameter of 25 mm(p<0.001). This initial evaluation of the effectiveness of the VCFCutilizing the embodiments disclosed herein shows that it is as effectiveas predicate filters at various vena cava diameters. The VCFC utilizingthe embodiments disclosed herein addresses the important limitations ofpredicate vena cava filters. Specifically, the VCFC utilizing theembodiments disclosed herein allows for bedside insertion and retrievalfor critically ill patients by combining a multilumen central venouscatheter and a truly retrievable vena cava filter. Further details onthe study of the ease of in vitro placement, retrieval, deployment, andclot-trapping effectiveness the Vena Cava Filter Catheter (VCFC)utilizing the embodiments disclosed herein may be found in Angel L,Guerra R, Atkinson E, et al. In Vitro Placement and Effectiveness of theAngel™ Vena Cava Filter Catheter.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described hereinabove without departing from thebroad concepts disclosed therein. It is understood, therefore, that thisdisclosure is not limited to the particular embodiments disclosed, butit is intended to cover modifications that may include a combination offeatures illustrated in one or more embodiments with featuresillustrated in any other embodiments. Various modifications, equivalentprocesses, as well as numerous structures to which the presentdisclosure may be applicable will be readily apparent to those of skillin the art to which the present disclosure is directed upon review ofthe present specification. Accordingly, this description is to beconstrued as illustrative only and is presented for the purpose ofenabling those skilled in the art to make and use the attachmentconfiguration described herein and to teach the best mode of carryingout the same.

What we claim is:
 1. A medical device coupled to a catheter, comprising:a. a generally tubular coupling projecting proximally from the medicaldevice and circumferentially engaged with the catheter, the generallytubular coupling having a proximal end and a distal end and furthercomprising a first plurality of cutouts positioned at one of or both theproximal end or distal end and positioned about a circumferential axisof the generally tubular coupling and a second plurality of cutouts inan intermediate section and positioned about the circumferential axis ofthe generally tubular coupling, the first plurality of cutouts and thesecond plurality of cutouts being geometrically deformable to allow fordiametric expansion diametric compression of the generally tubularcoupling onto the catheter; and b. a circumferentially compressivemember disposed concentrically about the generally tubular coupling andover the first plurality of cutouts and the second plurality of cutouts,and engaged with the generally tubular coupling and the catheter throughat least some of the first plurality of cutouts or second plurality ofcutouts.
 2. The medical device of claim 1, wherein the circumferentiallycompressive member is made of a first material and the catheter is madeof a second material and the first material and the second material arereflow joined.
 3. The medical device of claim 2, wherein the firstmaterial and the second material are polymeric materials.
 4. The medicaldevice of claim 3, wherein the first material and the second materialare the same polymeric material.
 5. The medical device of claim 2,wherein the first plurality of cutouts and second plurality of cutoutsare selected from the group consisting of: polygonal, circular,elliptical, open-ended circular, semi-circular, zig-zag, sinusoidal,coiled, and spaced line.
 6. The medical device of claim 2, wherein thefirst plurality of cutouts are configured with a width W extendinggenerally along a longitudinal axis of the proximal end and a height Hextending generally along a circumferential axis of the proximal end,wherein the width W of the cutouts is greater than the height H of thefirst plurality of cutouts and second plurality of cutouts.
 7. Themedical device of claim 1, wherein the first plurality of cutoutsfurther comprises substantially non-linear cutouts.
 8. The medicaldevice of claim 1, wherein the second plurality of cutouts furthercomprises substantially linear helically-oriented cutouts extendingalong the circumferential axis of the generally tubular coupling.
 9. Themedical device of claim 8, wherein the substantially linearhelically-oriented cutouts terminate in continuity with the firstplurality of cutouts.
 10. The medical device of claim 1, wherein thefirst plurality of cutouts further comprise substantially tear-dropshaped cutouts.
 11. The medical device of claim 10, further comprising aplurality of projections each comprising a substantially quadrilateralproximal portion and a substantially looped distal portion, thesubstantially looped distal portion forming the substantially tear-dropshaped cutouts.
 12. The medical device of claim 11, further comprisingsubstantially linear members projecting from the substantiallyquadrilateral proximal portion and coextensive with the medical device.13. A method for attaching a proximal end of a medical device to acatheter, comprising: a. disposing a thin tube over a catheter body andover at least a portion of the proximal end of the medical device,wherein the proximal end includes a plurality of cutouts; b. disposing acircumferentially compressive member coaxially over the thin tube; andc. joining the thin tube to the catheter body through the plurality ofcutouts to attached the proximal end of the medical device to thecatheter body.
 14. The method of claim 13, wherein step c, furthercomprises the step of reflowing a first material of the thin tube with asecond material of the catheter body.
 15. The method of claim 13,further comprising the step of forming the plurality of cutouts in ashape selected from the group consisting of: polygonal, circular,elliptical, open-ended circular, semi-circular, zig-zag, sinusoidal,coiled, and spaced line.
 16. The method of claim 13, further comprisingthe step of configuring the plurality of cutouts to have a width Wextending generally along a longitudinal axis of the proximal end and aheight H extending generally along an axial axis of the proximal end,wherein the width W of the cutouts is greater than the height H of theplurality of cutouts.
 17. The method of claim 13, wherein thecircumferentially compressive member is a heat shrink tube.
 18. Themethod of claim 13, further comprising removing the circumferentiallycompressive member from the thin tube after the joining step iscompleted.